Extending CurrentMember Check

Initially I was trying to use the DataObjectManager to save User Applications, which could than be copied to the Member Groups, but that proved to be beyond my ability.

Instead, I've created a Decorator to the Member Object that included the extra fields need. I've included an Approved Member check box and as an interim solution in my Template I add and <% if CurrentMember %> a <% control CurrentMember %> and then a check against the ApprovedMember field. But An Un-Approved Member can still login. I'd prefer if I could block them from Logging in. By creating an ApprovMember Control that be called from the template by extending normal security check to also check against the ApprovedMember Check Box.

Is this even possible? or is it getting more complex and I should try to work out the bugs of my previous concept?